Actually CD, you can get pregnant from anal sex. Tears can happen in and around the area of the anus that would allow for sperm to enter the vagina.
Heck, you can get pregnant just from having a guy orgasming outside and near your vaginal opening. If you’re wet enough the sperm can work it’s way into the vulva, find the vagina, and boom! You’re pregnant.
The only safe sex is no sex except with a partner you trust and a two or more different kinds of birth control.